The present invention relates generally to adjustable pedal systems for passenger vehicles, and, in particular, to an actuator assembly for controlling the position of pedals within passenger vehicles.
Adjustable pedal systems have been provided in vehicles to allow adjustment of the distance between the driver and the vehicle brake, accelerator and clutch pedals. These systems typically include an electro-mechanical actuator connected to an associated pedal, either directly or by a flexible cable. The actuator converts electrical power to rotational mechanical output power for moving the pedals to a desired position.
It is desirable for an adjustable pedal system to include a memory option that allows different users to set and automatically achieve user-defined position settings for the driver""s seat, mirrors, pedals, steering wheel, etc. In such a system, the position of the pedals must be known. This can be achieved, for example, by direct measurement of the pedal location compared to a stationary point. This position information is typically supplied to a control module that collects all pertinent subsystem information. As these pedal systems are integrated into systems that control safety related functions, e.g. air bag deployment, accurate position information concerning the pedals becomes critical.
For those adjustable pedal systems that require position information, the position of the pedals relative to a stationary point should be established. During installation of the actuator to the pedal assembly, this relationship may either be unknown or vary significantly from a preset condition. Therefore, it would be desirable to allow the position sensor to automatically calibrate to the pedal assembly within a predetermined travel actuation interval, e.g., one full-travel actuation interval, during assembly of the actuator to the pedal assembly.
In addition, audible noise is a significant feature differentiating actuators in adjustable pedal systems and all other in-cabin actuation applications. In some applications, a loud system is desirable to alert an operator that the actuator is being cycled. In other applications, a quiet system is desirable to keep in-cabin noise to a minimum.
There is therefore a need in the art for an efficient, reliable and cost-effective actuator design for a vehicle adjustable pedal system that overcomes the deficiencies of the prior art. There is a further need in the art for an efficient, accurate, and reliable position sensing mechanism that is self-calibrating for installation to an adjustable pedal system. There is still a further need in the art for a method of tuning the actuator for audible noise performance.
According to one aspect of the invention, there is provided an actuator including a motor having a drive shaft, and a gear train coupled to the drive shaft, wherein the gear train includes a plurality of output gears and an associated plurality of output ports for providing a mechanical output from the actuator. The gear train may be provided in a variety of configurations, and may include a worm gear and worm wheel configuration for reducing audible noise.
Various position sensing configurations, including non-contact pulse counting, non-contact analog sensing, and contact analog sensing, may be provided for determining the position of a movable element, e.g. one or more adjustable pedals of an adjustable pedal system. A controller, e.g. a microprocessor, may control the position of the movable element in response to a user input, and may facilitate auto-calibration of the element upon installation.
According to another aspect of the invention, there is provided an actuator including an isolator having an effective spring constant and damping constant. The isolator is coupled to at least one component, e.g. a motor, of the actuator for isolating the component from a remainder of the actuator. Tailoring of the spring and damping constants of the isolator allows audible noise tuning. According to another aspect of the invention, an isolator may be coupled to a sub-frame for isolating the sub-frame from a housing of the actuator, wherein the sub-frame is configured to enclose a plurality of components of the actuator.
According to yet another aspect of the invention, there is provided an actuator including a component isolator having an effective first spring constant and first damping constant, the component isolator coupled to at least one component of the actuator for isolating the component from a remainder of the actuator; and a subframe isolator having a second spring constant and second damping constant, the sub-frame isolator coupled to a sub-frame integral to a housing of the actuator, wherein the sub-frame encloses at least the component.